EVALUATION OF CIHANJUANG LANDSLIDE USING PHOTOGRAMMETRIC METHOD AND FINITE ELEMENT METHOD AT CIMANGGUNG DISTRICT, SUMEDANG REGENCY, WEST JAVA

• Main Author: Naufal Zayyan, Achmad
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/78559
• Institution: Institut Teknologi Bandung

The landslide that occurred on 9th January 2021 in Cihanjuang Village, Cimanggung District, Sumedang Regency, West Java, resulted in 40 deaths, 20 building units buried, 26 building units heavily damaged, and 350 building units under threat. In an effort to evaluate the occurrence of the landslides and to mitigate the affected area, research using photogrammetric method and back analysis is needed. This research was conducted with the aim of knowing the type and geometry of the Cihanjuang Landslide using the photogrammetric method and performing back analysis using the finite element method to determine the parameter value of the residual shear strength of the slip surface. The soil type was obtained from visual observations of core samples, cone penetration test, and laboratory analysis. It was found that the type of soil in the slip surface layer of the landslide was silty clay (fine-grained soil). From the determination of the type of landslide movement based on the results of processing 162 aerial photo data, it was obtained that the type of Cihanjuang Landslide movement is a rotational slip. Based on the materials that make up the slopes and the type of movement, the Cihanjuang Landslide is categorized as an earth slide. The geometry of the Cihanjuang Landslide has 141 meters in length and 39 meters in height, measured from the toe to the crown. This landslide has a coverage area of up to 4822.34 m2 and a moving landslide volume of 2319.77 m3 . Based on the back analysis using the finite element method, the residual shear strength parameter of the slip surface is the cohesion of 6.2 kPa and the internal shear angle of 8.2 o . The factors causing the Cihanjuang Landslide were the rising of the groundwater level and seepage due to fractures on the slopes.